[new cop] law of demeter

[yltsrc]

foo.bar.baz

read more to know why it is invalid code

[yujinakayama]

I think it's impossible for machines to detect violations of the law of Demeter.

This code does not violate the law, but RuboCop cannot know whether the method chaining descends a hierarchy or is a fluent interface.

def valid_method
  @message.downcase.strip.gsub(' ', '_')
end

[fuadsaud]

True. I don't think it's possible handling this mechanically.

[yltsrc]

these methods are just object modifications from standard library and active support
I think it may be possible to build list of methods like these and ignore them

[yujinakayama]

@yltsrc You should know what static code analysis is. It does not provide runtime class information, so there's no way to differentiate methods with a same name but different implementations.